Valve's ToGL source has been posted to GitHub and includes some release notes about its scope and implementation. There the firm notes that the code was plucked "directly from the DOTA2 source tree," and is supplied as-is and unsupported. As DOTA2 is a Valve Source Engine game potential users of this code are also told to "be wary that some parts are hardcoded to match Source Engine behavior; see CentroidMaskFromName() and ShadowDepthSamplerMaskFromName() in dxabstract.cpp".